Corrosion Inhibition Mechanism of an Ocimum Basilicum for Mild Steel in 1 M HCl: Electrochemical and Computational Insights

Abstract

Background: Corrosion is inevitable in every sector of the industry that involves metals and alloys. This process irreversibly destroys surface microstructure of the various materials used, and damages intrinsic structure of material. Plants and plant waste are natural resources as potential organic corrosion inhibitors due to competitive economic efficacy and environmental friendliness. Ocimum basilicum (OB) can be considered a potential alternative to conventional synthetic inhibitors due to its high inhibitory efficacy and long and short-term stability. Methods: This paper investigates the corrosion behavior of OB extract on MS surface in 1.0 M HCl using PDP, EIS and LPR techniques. Inhibition mechanism using PZC analysis, and proposing the possible reaction mechanism are made. Identifying the optimum adsorption configurations of major constituents is made using DFT analysis. Significant findings: This inhibitor conforms the rule of mixed-type. OB extract is a very effective inhibitor due to reducing the current densities on both sides of Ecorr, increasing the Rp, and decreasing the CPE. Because OB extract forms a robust protective film on the MS surface, the protective film provides high corrosion protection capability in terms of both long and short-term stability. DFT analysis confirms high inhibitory properties of the most abundant components in phytochemicals